Recovery method for password:
1. Restart computer
2. At grub menu press e
3. Navigate to linux kernel line
4. Add, after a space: init=/bin/sh rw
5. Press to boot: cntl+x
6. Run: /sbin/passwd <user>
7. Run: mount -o remount,ro /
8. Run: sync
9. Run: /sbin/reboot -f
At step 6, other things can also be done.
This process is linux essentials.
[Thanks Keith Owens in 1998]